This invention relates to systems and methods for accounting for individuals in emergencies in industrial settings using radio frequency identification.
Typically, in manufacturing facilities and similar settings, significant emphasis is placed on safety of people. Most jurisdictions have numerous regulations specifying minimum requirements and companies expend a great deal of effort and resources to improve the safety of such facilities.
In emergency situations, it is important to be able to account for individuals to appropriately direct rescue operations or take other actions in response to the emergency. As used herein, “emergency” or “emergency situation” means a situation in which a hazard condition is increased to a level sufficient to justify responsive action to mitigate the effects of such hazard. Examples of emergencies include fire, mechanical rupture, leakage of harmful gases or chemicals in an area, failure of protective structures or other change in the environment which change increases the hazard of the environment to an extent that jeopardizes the safety of individuals in or near the environment.
Many companies create response plans for emergencies. Typically, such response plans include instructions to remove non-essential individuals from the area of the increased hazard. One of the primary components in a typical response plan is to account for individuals, particularly individuals likely to be in the area of increased hazard. In many jurisdictions, government agencies may require that certain facilities have a method of accurately determining the location of people on site during and after emergencies. For example, in the United States, the Occupational Safety and Health Administration has promulgated regulations, such as 1910.38(c)(4), requiring certain facilities to have an emergency action plan that includes a procedure to account for all people on site during an emergency.
Commonly, accounting for individuals is performed by instructing individuals to gather at a specific location or locations, commonly referred to as mustering points, where a tally of the individuals is created, typically manually. Such tallies from mustering points are combined to determine whether all of the individuals have been accounted for. Combining the tallies typically involves communicating, either in person or by other means such as radio, with a command center or people charged with the duty to receive this information from the mustering points to form a consolidated tally. Such procedures are time consuming and prone to error. Delays in accounting for individuals can cause delays in directing appropriate response such as search and rescue efforts. Errors often lead to wasted time and resources and can unnecessarily jeopardize the safety of rescue personnel and of other individuals in need of aid.
Radio frequency identification (RFID) can be used as part of a method to account for individuals, particularly in case of an emergency. Unfortunately, RFID systems encounter significant difficulties providing accurate information in a setting in which a signal is subject to multiple reflective paths.
Radio frequency identification (RFID) technology has many applications ranging from toll road collection systems to asset management systems. Typically, an RFID system has one or more transmitters or transponders which are a combination of transmitter and receiver (also called “tags”) and at least one receiver or “reader”. Depending on the application, the receiver may also be accompanied by an additional transmitter and may thus be able to communicate with other devices. Such communication may use wires or may be wireless.
One of the major applications for RFID technology is to keep track of assets ranging from inventory to equipment or even people. In this type of application, the individual items which are to be tracked are attached to, co-located with, or otherwise associated with RFID tags.
RFID tags can be passive, semi-passive or active. Passive tags do not have an internal power source. A small electric current is generated by energy intercepted from an incoming radio frequency signal which provides enough power for the tag to send a responding signal. The tags' responding signal may simply be an identification number, however, passive tags can be designed to store additional information, for example in non-volatile memory. Such stored additional information may be transmitted by the tag in response to an incoming radio frequency signal or can be otherwise obtained from the tag. A device typically referred to as a reader, reads the signal from the tag. The reader may be part of the device which initially sent a signal to the RFID tag or it can be a separate device. The lack of an internal power source allows passive tags to be relatively small in comparison to other types of tags. However, the lack of internal power also limits the tag's signal strength. Typically, passive tags can not send a signal more than about 2 meters and the distance is usually much less.
Semi-passive tags, also prompted by an incoming radio frequency signal, contain a small battery allowing a more powerful response signal and, therefore, are typically easier to read than passive tags. Because a battery is present, semi-passive tags generally can not be made as thin as passive tags.
Active tags have an internal power source which allows the tag to send out a signal without being prompted by an incoming signal. Typically a signal is sent by an active tag on a predetermined periodic basis, for example every 2 seconds. However, some active tags may include sensors or other devices and may alter the pattern or content of its signal based on the data output from such sensors. For example, an active tag may be accompanied by a thermocouple device for sensing temperature. Such a tag could be programmed to start signaling only once a certain temperature is sensed. Such a tag could also be programmed to vary the period between tag transmissions depending upon the temperature sensed. Such a tag could also be programmed to alter a variety of other characteristics of its emitted signal based upon sensed temperature.
Passive tags are frequently used as identifications badges or for access control where a user brings the tag in the vicinity of a reader. Such a reader generally transmits a signal and elicits a response from the passive tag which includes information identifying the tag. The identification information is used, typically by other systems, to verify the credentials of the tag. Passive tags are also used for inventory control or theft deterrence wherein a tag is affixed to an article and, as the article and tag pass in the vicinity of a reader, the information may be logged or an alarm triggered.
Active tags are commonly used on vehicles as a method to pay tolls. Typically, the tag passes within range of a reader which reads the signal and sends the information to a gateway or central computer which charges the toll to the user's account.
Another example of use is described in U.S. Published Patent Application 2004/0160323 which describes use of RFID transponders for a security system. U.S. Published Patent Application 2005/0024183 describes an RFID tag which is part of a uniform or other clothing and is used for identification.
There is great interest in using RFID technology to locate objects or people. EP 1,566,756 describes a system for tracking objects. JP2004288119 describes use of RFID technology to track entry/exit of people for security and safety purposes.
A common method of tracking inventory or people using RFID tags is to use passive tags and place RFID readers in locations where such inventory or people are expected to pass, for example at doorways or other points of entry or egress. However, such a system is limited in that it can only determine that the object or person passed near the reader. For such a system to continue to provide location information, readers would need to be placed throughout the entire coverage area. But readers for passive RFID tags have a very limited range, typically less than one meter, so it is impractical to track inventory or people in a large area. It is also impractical in an area with a large number of entryways or in an open area. Active RFID systems can be used to locate an object or person in an area so that actual location can be determined. However such systems often have great difficulty in determining location with an accuracy of one meter or less. This difficulty is greatly increased in a setting where there are multiple reflective paths which a signal may take before reaching a reader. For this reason, RFID location systems have not been useable in dense metal areas found in industrial settings such as a petroleum refinery, petrochemical plant, or other similar environments to provide accurate location information of people or objects. In such settings, signal quality degradation and signal reflection interfere with the ability to accurately locate a person or item within processing units or similar environments densely populated with metal equipment or structures. There is a need for a system for accurately locating people or items in such industrial settings.
A possible system which could be considered to account for people is a proximity-based system. Such a system typically requires each individual to either swipe an identification card through a reader or bring an identification card within a few inches of a reader, a process commonly referred to as “swiping in” or “swiping out” of a location. Unfortunately, people often neglect to swipe in or out of a location or often follow another individual who has swiped in or out without swiping in or out themselves (known as “piggybacking”). Such occurrences can lead to severe difficulties during emergencies and can expose rescue personnel to unnecessary dangers. For example, if a person neglects to swipe out of a location, rescue personnel responding to an emergency may believe that the individual is still in that location and may engage in an unneeded search and rescue operation.
The problem of people neglecting to swipe in or out of a location is compounded in an emergency because people trying to exit a location as swiftly as possible are less likely to take the additional time and effort required to swipe out of the location. As noted above, such a condition can lead to misinformation regarding an individual's location and can result in misdirection of rescue efforts. Additionally, in many industrial sites, proximity based systems could only be effectively used in enclosed or fairly contained areas. Such systems are not effective at accounting for individuals in open areas or in areas without specific exit points. An additional undesirable result of relying on a proximity based system is that requiring individuals to swipe in and out of every location, even when retrieving a tool or taking a break, etc., can lead to wasted time and effort and overall work inefficiencies.
In an effort to require people to swipe in and out of a location, some locations include electronic turn-style type gates, typically a proximity-based RFID system, which an individual must use to enter and exit a location. Such a system is not effective in many industrial settings because an area may not have specified entrance and exit points. Additionally, such turn-styles are typically designed to automatically remain open in an emergency situation to allow occupants to exit a location quickly which greatly reduces the accuracy in accounting for the occupants.
Other systems for accounting for individuals in emergencies involve manual identification of individuals at specified muster locations. Such manual systems require communication between mustering stations or to a central location at which a complete tally of individuals can be generated to compare with a list of individuals known to be on site.
Because of such signal degradation and general difficulty in using RFID to locate individuals in environments densely populated with metal, such as those found in industrial environments, many facilities rely on a manual system where designated individuals record identities of people at specified mustering points. Such systems are typically time consuming and are prone to error because individuals may not show up at a designated muster station or may not be counted due to manual error. Furthermore, such systems do not provide any information about the current locations of individuals that were not accounted for at mustering stations.
Because of the significant inaccuracies in such manual systems, in some cases, individuals may be accidentally omitted from the tally or may otherwise not be accounted for. Often, no reliable information is available as to the individuals' present whereabouts or last known whereabouts. This can result in wasted time and effort spent in locating individuals who are not in danger. In some scenarios, emergency rescue personnel may be unnecessarily exposed to significant hazards searching for an unaccounted for individual because of misinformation as to the individual's possible location.
Ultra wideband (UWB) systems have been described in U.S. Pat. Nos. 6,054,950, 6,882,315 and 7,209,523 which are each fully incorporated by reference herein. U.S. Pat. No. 6,882,315 describes an UWB architecture designed to locate objects and compensate for phase skew between counters of multiple monitoring stations in which counters are used to measure differential arrival times of received signals. U.S. Pat. No. 6,054,950 describes an UWB system for object location over large areas. U.S. Pat. No. 7,209,523 describes a wide variety of techniques for the design of UWB transmitters and receivers which can be used in object location systems.
We have discovered a method for accounting for individuals in emergencies useable in industrial settings such as refineries, petrochemical plants, and other facilities that have areas densely populated with metal structures or equipment. We have discovered that UWB systems can be adapted to operate in an industrial setting, such as a refinery or chemical plant, and can effectively locate objects and people despite signal degradation and multi-path signals and can be used as part of a method to account for people in emergencies.